67 research outputs found

    Hydrothermal synthesis and characterization of zeolite from Malaysia’s natural kaolin for adsorption of sodium ion (NA+) from seawater

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    Zeolite-A is widely known as aluminosilicate mineral that has been intensively used as an adsorbent in the adsorption process for desalination. Desalination is a technique to eliminate sodium ion and other minerals in the water. Because of the nature of seawater, which is very salty, the main purpose of the removal of sodium ion from seawater is to produce a source of clean drinking water. The capability of zeolite-A as an adsorbent makes it suitable to remove sodium ion from seawater. The raw kaolin from a different location (Perak and Johor) that acts as the main source of silica and alumina has been successfully studied to synthesized and transform into the Zeolite�A. The proposed synthesis of zeolite-A from kaolin has been reduced the cost of using synthetic reagent and high energy utilization. The various operating parameters to synthesis zeolite-A from both low-grade kaolin (Perak and Johor) were investigated to produce high crystallinity of zeolite. The alkaline solution (2-3 M NaOH) was added as a modification method for their conventional hydrothermal synthesis process. The calcination and crystallization process was recognized as an important processing stage for the synthesis. For the metakaolin process, the temperature 650 0C and time 240 minutes were used. The crystallization time of 12-16 hours with an aging treatment time of 24 hours was selected in the synthesizing of zeolite. The successful of synthesized Zeolite-A was further characterized by XRD, FESEM, FTIR, PSA and BET. The composition percentage of kaolinite from Perak kaolin (84 %) is higher compared to the Johor kaolin (40.6 %). As demonstrated in this work, Perak kaolin was successfully synthesized into Zeolite-A which give higher crystallinity percentage, 72.97 % compared to Johor kaolin, 46.72 % under 24 hours aging, with 2M NaOH and 12 hour crystallization time. The higher percentage of kaolinite from Perak kaolin gives higher crystallinity percentage of synthesizing zeolite-A compared to Johor kaolin. In addition, the BET surface area of Zeolite-A is higher, 5.26 m2 /g compared to natural zeolite, 2.9 m2 /g. The performance of adsorption capacity of sodium ion (Na+ ) toward synthesized Zeolite-A was further analyzed by batch adsorption analysis (Isotherm and Kinetic Model) and column adsorption analysis (Breakthrough curve model). The various parameter was applied to the batch experiment (Zeolite-A dosage, time, initial sodium ion concentration and volume) and column experiment (Zeolite-A dosage, initial sodium ion concentration and flow rate). For batch adsorption analysis, both the Langmuir model and Freundlich model were used to analyze the adsorption of sodium ion toward Zeolite-A. Langmuir isotherm model shows slightly better fitted with the correlation coefficient, R2 = 0.9074 compared to Freundlich isotherm, R 2= 0.9028. The result from the kinetic model shows the intra particle diffusion model gives better fitted with R2 value is 0.9117 compared to pseudo first order (R2= 0.732) and pseudo second order (R2= 0.8276). In addition, the calculated value of adsorption capacity at equilibrium, qe, is 88.4 mg/g by intra particle diffusion model gives the closest to the experimental value of qe, (92 mg/g) compared to pseudo first order (qe= 205.36 mg/g) and pseudo second order (qe= 104.1 mg/g). For column adsorption analysis, breakthrough capacity, qB was increased by increasing the bed height of zeolite-A and initial sodium ion concentration but decrease when increasing the flow rate. The column kinetic model shows the Adam Bohart model slightly better fitted with R2 range is 0.86-0.95 for flow rate, R2 = 0.82- 0.93 for bed height and R2 = 0.90-0.95 for initial sodium ion concentration compared to Thomas model, R2 = 0.84-0.94 for flow rate, R2 = 0.72-0.89 for bed height and R2= 0.78-0.88 for initial sodium ion concentration and Yoon and Nelson model, R2 = 0.84- 0.94 for flow rate, R2 = 0.69-0.89 for bed height and R2 = 0.78-0.87 for initial sodium ion concentration. It can be concluded that the performance of synthesizing zeolite-A from Perak kaolin was capable of adsorbing sodium ion from seawater solution

    A revised inventory of Antarctic subglacial lakes

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    The locations and details of 145 Antarctic subglacial lakes are presented. The inventory is based on a former catalogue of lake-type features, which has been subsequently reanalysed, and on the results from three additional datasets. The first is from Italian radio-echo sounding (RES) of the Dome C region of East Antarctica, from which 14 new lakes are identified. These data also show that, in a number of occasions, multiple take-type reflectors thought previously to be individual lakes are in fact reflections from the same relatively large take. This reduces the former total of lake-type reflectors by six, but also adds a significant level of information to these particular lakes. The second dataset is from a Russian survey of the Dome A and Dome F regions of East Antarctica, which provides evidence of 18 new lakes and extends the coverage of the inventory considerably. The third dataset comprises three airborne RES surveys under-taken by the US in East Antarctica over the last five years, from which forty three new lakes have been identified. Reference to information on Lake Vostok, from Italian and US surveys taken in the last few years, is now included

    Nuchal translucency of 3.0-3.4 mm an indication for NIPT or microarray? Cohort analysis and literature review

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    Introduction: Currently fetal nuchal translucency (NT) ≥3.5 mm is an indication for invasive testing often followed by chromosomal microarray. The aim of this study was to assess the risks for chromosomal aberrations in fetuses with an NT 3.0-3.4 mm, to determine whether invasive prenatal testing would be relevant in these cases and to assess the residual risks in fetuses with normal non-invasive prenatal test (NIPT) results. Material and methods: A retrospective study and meta-analysis of literature cases with NT between 3.0 and 3.4 mm and 2 cohorts of pregnant women referred for invasive testing and chromosomal microarray was performed: Rotterdam region (with a risk >1:200 and NT between 3.0 and 3.4 mm) tested in the period July 2012 to June 2019 and Central Denmark region (with a risk >1:300 and NT between 3.0 and 3.4 mm) tested between September 2015 and December 2018. Results: A total of 522 fetuses were referred for invasive testing and chromosomal microarray. Meta-analysis indicated that in 1:7.4 (13.5% [95% CI 8.2%-21.5%]) fetuses a chromosomal aberration was diagnosed. Of these aberrant cases, 47/68 (69%) involved trisomy 21, 18, and 13 and would potentially be detected by all NIPT approaches. The residual risk for missing a (sub)microscopic chromosome aberration depends on the NIPT approach and is highest if NIPT was performed only for common trisomies–1:21 (4.8% [95% CI 3.2%-7.3%]). However, it may be substantially lowered if a genome-wide 10-Mb resolution NIPT test was offered (~1:464). Conclusions: Based on these data, we suggest that the NT cut-off for invasive testing could be 3.0 mm (instead of 3.5 mm) because of the high risk of 1:7.4 for a chromosomal aberration. If women were offered NIPT first, there would be a significant diagnostic delay because all abnormal NIPT results need to be confirmed by diagnostic testing. If the woman had already received a normal NIPT result, the residual risk of 1:21 to 1:464 for chromosome aberrations other than common trisomies, dependent on the NIPT approach, should be raised. If a pregnant woman declines invasive testing, but still wants a test with a broader coverage of clinically significant conditions then the genome-wide >10-Mb resolution NIPT test, which detects most aberrations, could be proposed

    Nuchal translucency of 3.0-3.4 mm an indication for NIPT or microarray? Cohort analysis and literature review

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    Introduction: Currently fetal nuchal translucency (NT) ≥3.5 mm is an indication for invasive testing often followed by chromosomal microarray. The aim of this study was to assess the risks for chromosomal aberrations in fetuses with an NT 3.0-3.4 mm, to determine whether invasive prenatal testing would be relevant in these cases and to assess the residual risks in fetuses with normal non-invasive prenatal test (NIPT) results. Material and methods: A retrospective study and meta-analysis of literature cases with NT between 3.0 and 3.4 mm and 2 cohorts of pregnant women referred for invasive testing and chromosomal microarray was performed: Rotterdam region (with a risk >1:200 and NT between 3.0 and 3.4 mm) tested in the period July 2012 to June 2019 and Central Denmark region (with a risk >1:300 and NT between 3.0 and 3.4 mm) tested between September 2015 and December 2018. Results: A total of 522 fetuses were referred for invasive testing and chromosomal microarray. Meta-analysis indicated that in 1:7.4 (13.5% [95% CI 8.2%-21.5%]) fetuses a chromosomal aberration was diagnosed. Of these aberrant cases, 47/68 (69%) involved trisomy 21, 18, and 13 and would potentially be detected by all NIPT approaches. The residual risk for missing a (sub)microscopic chromosome aberration depends on the NIPT approach and is highest if NIPT was performed only for common trisomies–1:21 (4.8% [95% CI 3.2%-7.3%]). However, it may be substantially lowered if a genome-wide 10-Mb resolution NIPT test was offered (~1:464). Conclusions: Based on these data, we suggest that the NT cut-off for invasive testing could be 3.0 mm (instead of 3.5 mm) because of the high risk of 1:7.4 for a chromosomal aberration. If women were offered NIPT first, there would be a significant diagnostic delay because all abnormal NIPT results need to be confirmed by diagnostic testing. If the woman had already received a normal NIPT result, the residual risk of 1:21 to 1:464 for chromosome aberrations other than common trisomies, dependent on the NIPT approach, should be raised. If a pregnant woman declines invasive testing, but still wants a test with a broader coverage of clinically significant conditions then the genome-wide >10-Mb resolution NIPT test, which detects most aberrations, could be proposed

    Numerical nonlinear inelastic analysis of stiffened shells of revolution. Volume 4: Satellite-1P program for STARS-2P digital computer program

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    A special data debugging package called SAT-1P created for the STARS-2P computer program is described. The program was written exclusively in FORTRAN 4 for the IBM 370-165 computer, and then converted to the UNIVAC 1108

    Blind Search for Optimal Wiener Equalizers Using an Artificial Immune Network Model

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    This work proposes a framework to determine the optimal Wiener equalizer by using an artificial immune network model together with the constant modulus (CM) cost function. This study was primarily motivated by recent theoretical results concerning the CM criterion and its relation to the Wiener approach. The proposed immune-based technique was tested under different channel models and filter orders, and benchmarked against a procedure using a genetic algorithm with niching. The results demonstrated that the proposed strategy has a clear superiority when compared with the more traditional technique. The proposed algorithm presents interesting features from the perspective of multimodal search, being capable of determining the optimal Wiener equalizer in most runs for all tested channels

    Fuel Optimal Maneuvers for Multispacecraft Interferometric Imaging Systems

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76545/1/AIAA-20178-139.pd

    Bone material properties and response to teriparatide in osteoporosis due to WNT1 and PLS3 mutations

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    Context: Patients with osteoporosis-associated WNT1 or PLS3 mutations have unique bone histomorphometric features and osteocyte-specific hormone expression patterns. Objective: To investigate the effects of WNT1 and PLS3 mutations on bone material properties. Design: Transiliac bone biopsies were evaluated by quantitative backscattered electron imaging, immunohistochemistry, and bone histomorphometry. Setting: Ambulatory patients. Patients: Three pediatric and eight adult patients with WNT1 or PLS3 mutations. Intervention: Bone mineralization density distribution and osteocyte protein expression was evaluated in 11 patients and repeated in six patients who underwent repeat biopsy after 24 months of teriparatide treatment. Main outcome measure: Bone mineralization density distribution and protein expression. Results: Children with WNT1 or PLS3 mutations had heterogeneous bone matrix mineralization, consistent with bone modeling during growth. Bone matrix mineralization was homogenous in adults and increased throughout the age spectrum. Teriparatide had very little effect on matrix mineralization or bone formation in patients with WNT1 or PLS3 mutations. However, teriparatide decreased trabecular osteocyte lacunae size and increased trabecular bone FGF23 expression. Conclusion: The contrast between preserved bone formation with heterogeneous mineralization in children and low bone turnover with homogenous bone mineral content in adults suggests that WNT1 and PLS3 have differential effects on bone modeling and remodeling. The lack of change in matrix mineralization in response to teriparatide, despite clear changes in osteocyte lacunae size and protein expression, suggests that altered WNT1 and PLS3 expression may interfere with coupling of osteocyte, osteoblast, and osteoclast function. Further studies are warranted to determine the mechanism of these changes.Peer reviewe

    Origen de la calidad del agua del acuífero colgado y su relación con los cambios de uso de suelo en el Valle de San Luis Potosí

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    "La historia de la ciudad San Luis Potosí se remonta al siglo XVI. Con el descubrimiento de yacimientos de oro y plata y la presencia de cuerpos de agua en el valle, fue fundada la ciudad San Luis Minas del Potosí, dando lugar a los dos primeros usos de suelo, urbano y minero. A partir del siglo XVII, el uso de suelo agrícola se desarrolló en huertos y fue relegado a la periferia de la zona urbana en el transcurso del tiempo. Finalmente el uso de suelo industrial surgió de manera importante en la segunda mitad del siglo XX. En la actualidad los tres usos de suelo existentes dentro del Valle de San Luis Potosí son el urbano, agrícola e industrial. A través de una campaña de muestreo hidrogeoquímico en octubre de 2008, con 44 muestras de norias y 3 de manantiales dentro del valle, se evaluaron parámetros físico-químicos, cationes, aniones y elementos traza. En los tres usos de suelo en la zona de estudio fueron detectados niveles importantes de nitratos, sulfatos, cloruros, conductividad eléctrica, coliformes totales y fecales; sin embargo, en la zona urbana existen anomalías puntuales de metales pesados principalmente de mercurio, bario, estroncio, cadmio, plomo, fósforo y plata, relacionadas a las antiguas actividades mineras y a la industria activa en la zona. Mientras que en la zona agrícola, la presencia de metales está asociada a los canales a cielo abierto que también reciben agua del Tanque Tenorio y éste a su vez de la zona industrial. En la zona industrial se detectaron grandes anomalías de tipo puntual en casi todos los metales pesados analizados; la principal fuente de estos contaminantes corresponden a un terreno industrial activo. Este trabajo está enfocado a evaluar el impacto que ha generado la actividad antropogénica sobre el acuífero colgado del Valle de San Luis Potosí desde inicios de la fundación de la ciudad hasta la actualidad, utilizando la calidad del agua como herramienta de análisis.""The history of San Luis Potosi City dates back to the sixteenth century. With the discovery of gold and silver deposits and the presence of water bodies in the valley, the city of San Luis Minas Potosí was founded, leading to the first two uses of land: urban and mining. From the seventeenth century, agricultural land developed in orchards and, over time, was relegated to the periphery of the urban area. Finally, industrial land use emerged significantly in the second half of the twentieth century. Currently the three existing land uses within the Valley of San Luis Potosi are urban, agricultural and industrial. Through a hydrogeochemical sampling campaign in October 2008 with 44 samples from wells and 3 from springs within the valley, we assessed physical and chemical parameters, cations, anions and trace elements. In the three land uses within the study area, we detected significant levels of nitrates, sulphates, chlorides, electrical conductivity, total and fecal coliforms; but in urban areas there are punctual anomalies of heavy metals, mainly mercury, barium, strontium, cadmium, lead, phosphorus and silver related to former mining and active industry in the area. However, in the agricultural zone, the presence of metals is associated with open channels, which also receive water from the Tanque Tenorio and this in turn from the industrial area. In the industrial area, puntual anomalies were detected in almost all heavy analyzed metals; the main source of these pollutants corresponds to an active industrial area. This work aims to evaluate the impact of anthropogenic activity in the perched aquifer of the Valley of San Luis Potosí since the city's foundation to the present, using water quality as an analytical tool.

    Soft subdermal implant capable of wireless battery charging and programmable controls for applications in optogenetics

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    Optogenetics is a powerful technique that allows target-specific spatiotemporal manipulation of neuronal activity for dissection of neural circuits and therapeutic interventions. Recent advances in wireless optogenetics technologies have enabled investigation of brain circuits in more natural conditions by releasing animals from tethered optical fibers. However, current wireless implants, which are largely based on battery-powered or battery-free designs, still limit the full potential of in vivo optogenetics in freely moving animals by requiring intermittent battery replacement or a special, bulky wireless power transfer system for continuous device operation, respectively. To address these limitations, here we present a wirelessly rechargeable, fully implantable, soft optoelectronic system that can be remotely and selectively controlled using a smartphone. Combining advantageous features of both battery-powered and battery-free designs, this device system enables seamless full implantation into animals, reliable ubiquitous operation, and intervention-free wireless charging, all of which are desired for chronic in vivo optogenetics. Successful demonstration of the unique capabilities of this device in freely behaving rats forecasts its broad and practical utilities in various neuroscience research and clinical applications.ope
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